1. Field of the Invention
The invention relates to downhole electrical connections made up in a wet environment. More particularly, the invention relates to downhole sealed connectors which self-clean upon makeup to avoid contamination in the connection.
2. Prior Art
Downhole power/signal wire connection/disconnection has always been a problem for the industry. More specifically, because the downhole environment is extremely hostile to electric connection (salt water, fresh water, acids, etc.), it has traditionally been thought that a reliable xe2x80x9cwet connectionxe2x80x9d could not be effected. Prior art systems have attempted to create wet connection that employ in the downhole environment but have met with only limited reliability. The prior art connectors are quite small and require an unlikely degree of precision when the connection is to be made, for example, 5000 feet below the surface. Therefore, although these connectors are reasonably capable of providing a good electrical connection at the surface in modern wellbore systems, they fail to solve the need for connection of an uphole string to a downhole string far below the surface. Such connections are required for the plurality of tools incorporated which require power and instructions.
The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the wet connector/disconnector embodiments of the invention.
All of the embodiments of the invention avoid the need to stab-in a small connector. The stabbing-in of the tubing itself is all that is necessary to make up the connection. This is a substantial benefit to the art in view of the growing use of electrically activated dowahole tools. The wet connect/disconnect ensures reliability of such systems due to an increase in the likelihood of connection and a reduction in the care needed to effect the connection.
Most of the embodiments disclosed herein employ an insulator that protects a conductor installed with the downhole equipment. The insulator may be rubber, plastic, metal, a grease, etc. with the joining principal being to maintain the conductor in a very clean condition. Additionally, some of the embodiments further include a hydraulic fluid wash to ensure the conductor does not become contaminated when the insulator is pierced or otherwise removed by the string/connector being stabbed in. Generally, the conductor on the stab-in tool is also protected by one or more of the insulators noted above.
Other embodiments do not employ conductor insulators on the downhole string but rely upon a cleansing action of the uphole string upon stab-in to remove any debris or oxidation that may have accumulated on the downhole conductors.
With each of the embodiments disclosed herein, the process of stabbing in causes certain events to occur which lead to secure reliable connections.
In addition to the ability to wet connect, some of the embodiments herein allow for a wet disconnect and reconnect which is advantageous for situations requiring such activity. In one embodiment, a portion of the uphole string is left connected to the downhole string. This leaves the connection made during stabbing-in undisturbed. Rather a piece of the uphole section, which itself provides a new insulated conductor (or not insulated) for a subsequent stab-in procedure, is left behind. Thus, in the event that the uphole section of string needs to be pulled, a reconnection may be made at a later time in the same manner as the original conductor mating. In order to be able to leave a section downhole, a switch section must also be employed to break the connection with the upper string. The switch section must break the connection in a sealed environment to prevent a short circuit upon reconnecting the uphole string.